The number #1 rule in crypto is: Not your keys, not your crypto.
But there is a number #0 rule that nobody is talking about.
The first thing you have to consider before investing in crypto is that this is a WILD RIDE. You should just invest the money that you can afford to lose.
And by "lose" y mean literally, that you can see your investment go to 0€ in minutes. And you should be able to manage that, all the feelings that we as humans have will be tested in crypto!
Crypto has been testing my emotions since 2017, and I have been in periods of big euphoria and other periods were I felt the opposite.
Actually I am managing quite good this dips, I am convinced about the technology and I am truly a believer. If the prices go down, I will just invest more. And I will always have in mind that this money is money that I don't need.
Be careful with the projects you select for investing, some can seem like super-safe but you should do a lot of research if you want to put a large sum of money into any project.
Recently the developer Chef Nomi founder of SushiSwap sold 20,000 ETH and 2,500,000 SUSHI from the developer fund. The funds were supposed to be used to finance future development of the project. And this happens everyday in this space, be careful!